sedimentary
Flint / Chert Pebble
Microcrystalline quartz (SiO2)
Hardness of 7 on the Mohs scale, colors typically range from grey, white, to black, waxy to vitreous luster, amorphous or cryptocrystalline structure, conchoidal fracture with no true cleavage, specific gravity of 2.60 to 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, colors typically range from grey, white, to black, waxy to vitreous luster, amorphous or cryptocrystalline structure, conchoidal fracture with no true cleavage, specific gravity of 2.60 to 2.65.
Formation & geological history
Formed through the chemical replacement of calcium carbonate in limestone or chalk by silica-rich solutions in marine environments over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire. Today primarily collected as a beach pebble, used in decorative landscaping, or as aggregate.
Geological facts
Flint has been utilized by humans for hundreds of thousands of years due to its predictable conchoidal fracture, allowing prehistoric humans to shape extremely sharp edges.
Field identification & locations
Commonly found along chalk cliffs, beaches, and riverbeds. Identified by its smooth, water-worn exterior, waxy luster on broken surfaces, and extreme hardness.
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